diff --git a/crates/oxide_compiler/src/emitter.rs b/crates/oxide_compiler/src/emitter.rs
index b9c89d8..92844fd 100644
--- a/crates/oxide_compiler/src/emitter.rs
+++ b/crates/oxide_compiler/src/emitter.rs
@@ -1029,9 +1029,7 @@ impl Compiler {
                     _ => OpCode::CALL,
                 };
                 ctx.emit(opcode::encode(op, callee_reg, this_reg, first_arg_reg));
-                if matches!(op, OpCode::CALL_NATIVE) {
-                    ctx.emit(arg_regs.len() as u32);
-                }
+                ctx.emit(arg_regs.len() as u32);
                 // Copy result from regs[0] into a dedicated register so multiple
                 // call expressions don't overwrite each other.
                 let result_reg = ctx.alloc_reg();
diff --git a/crates/oxide_vm/src/vm.rs b/crates/oxide_vm/src/vm.rs
index e3455f3..77e6fbc 100644
--- a/crates/oxide_vm/src/vm.rs
+++ b/crates/oxide_vm/src/vm.rs
@@ -1191,12 +1191,13 @@ impl Vm {
                         if !obj_ptr.is_null() {
                             let obj = unsafe { &*obj_ptr };
                             if obj.is_function() {
-                                if obj.native_fn().is_some() {
-                                    // Native call - use extension word for arg_count
-                                    let ext = self.bytecode[self.pc];
-                                    self.pc += 1;
-                                    let arg_count = (ext & 0xFF) as usize;
+                                // Always consume extension word for arg_count
+                                let ext = self.bytecode[self.pc];
+                                self.pc += 1;
+                                let arg_count = (ext & 0xFF) as usize;
 
+                                if obj.native_fn().is_some() {
+                                    // Native call
                                     let mut args_buf = [0u8; 257];
                                     args_buf[0] = this_reg;
                                     for i in 0..arg_count.min(256) {
diff --git a/crates/oxide_vm/tests/regression_tests.rs b/crates/oxide_vm/tests/regression_tests.rs
index 5ea070b..1997b5e 100644
--- a/crates/oxide_vm/tests/regression_tests.rs
+++ b/crates/oxide_vm/tests/regression_tests.rs
@@ -59,9 +59,10 @@ fn regression_recursion_depth_limit() {
 
 #[test]
 fn regression_throw_statement_errors() {
-    assert_eq!(
-        eval("throw 'error'"),
-        "vm error: opcode THROW not yet implemented"
+    let result = eval("throw 'error'");
+    assert!(
+        result.contains("uncaught"),
+        "expected uncaught, got: {result}"
     );
 }